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Power efficient, high throughput system for optical wireless communications

An optimal modulation protocol that offers an energy efficient, high-data-rate and high-throughput option for optical wireless communications such as LiFi, in which light emitting diodes (LEDs) used for illumination also serve as data transmitters via the visible or infrared light spectrum.

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  • Internet of Things (IoT)
  • In home visible light communication systems with dimming capabilities
  • M2M low power high bandwidth communication links


  • Proof of concept 


  • PCT patent PCT/GB2017/051423 filed 22 May 2017


  • Licensing and/or collaborative research


LiFi utilises the power of LED light to create a fast, bidirectional, fully networked form of visible light communication, with diverse applications ranging from in-flight message systems to the Internet of Things. Since its introduction, LiFi technology has continued to innovate and develop, but to date the inherent properties of optical wireless communications (OWC) have called for a variety of trade-offs to be made between acceptable spectral loss, energy efficiency and signal processing complexity.


University of Edinburgh researchers have now developed Augmented Spectral Efficiency – Discrete MultiTone (ASE-DMT), a new modulation technique for OWC systems like LiFi, which utilises the properties of symmetry and tiered superpositioning within the frequency domain in order to reduce spectral loss and improve energy efficiency at a reasonable computational complexity. Its temporal-free modulation structure requires no time-delay in the transmitter, leading to simpler transmitter/receiver designs, faster communications and smaller buffer size requirements. The simple and clever structure of the ASE-DMT can be readily implemented into existing communications firmware and hardware.


  • Significantly increased energy efficiency and decreased spectral loss compared to other modulation techniques with a simple design that implements hierarchical loading in the frequency domain
  • Temporal-free modulation reduces communication delay, memory requirements and computational complexity
  • Low implementation cost without significant disruption of infrastructure due to easy adaptation to current firmware / hardware


Islim, Mohamed Sufyan, and Harald Haas. “Augmenting the spectral efficiency of enhanced PAM-DMT-based optical wireless communications.” Optics Express 24.11 (2016): 11932-11949.

Please note, header image is purely illustrative.

Source: image pixaby

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